JP5779117B2 - Reactor water pipe cleaning method - Google Patents

Description

  The present invention relates to a method for cleaning a reactor water supply system pipe (reactor water supply pipe) communicating with a reactor pressure vessel.

  Generally, when a nuclear power plant is constructed, piping connected to the reactor pressure vessel is cleaned in advance. In particular, the reactor water supply pipe is sufficiently cleaned so that residual foreign matters in the pipes (hereinafter simply referred to as foreign matters) such as iron rust and cladding are not brought into the reactor pressure vessel during subsequent reactor operation.

  Conventionally, as a method for cleaning a reactor water supply pipe at the time of construction of a nuclear power plant, a method for cleaning a reactor water supply pipe with cleaning water stored in advance in a condenser constituting a reactor condensate system is known ( For example, see Patent Document 1). FIG. 7 is a schematic diagram for explaining a conventional method of cleaning a reactor water supply pipe. In FIG. 7, descriptions of the main steam system, the control rod drive mechanism, the reactor containment vessel, and the like are omitted.

  As shown in FIG. 7, in the conventional cleaning method, before the fuel is loaded into the reactor pressure vessel 12a, the condensate pump 15a is driven and the cleaning water W stored in the condenser 14 is recovered. The reactor water supply pipe 15 is washed by flowing through the water supply pipe 15 through the water filter 15b and the condensate demineralizer 15c. In this cleaning method, the waste water after cleaning the reactor water supply pipe 15 is collected in the temporary pool 13 detachably disposed in the reactor pressure vessel 12a. Incidentally, reference numeral 15h in FIG. 7 is a reactor water supply line valve.

Japanese Patent No. 3580636

However, in the conventional cleaning method (see, for example, Patent Document 1), the temporary pool 13 must be arranged in a limited narrow space in the reactor pressure vessel 12a, and thus a large-capacity temporary pool 13 is used. There was a problem that could not be done. Therefore, in the conventional cleaning method, it is difficult to clean the reactor water supply pipe 15 with a large amount of cleaning water. In addition, if the waste water overflows from the temporary pool 13, foreign matter in the reactor water supply pipe 15 contained in the waste water may be brought into the reactor pressure vessel 12a, which is coupled with the small capacity of the temporary pool 13. There has been a problem that the flow rate of the cleaning water in the reactor water supply pipe 15 cannot be sufficiently increased.
Therefore, there has been a demand for a method for cleaning a reactor water supply pipe that has a higher cleaning efficiency than before by cleaning the inside of the reactor water supply pipe with a large amount of cleaning water having a higher flow rate than before.

  Then, the subject of this invention is providing the washing | cleaning method of the reactor water supply pipe which is excellent in washing | cleaning efficiency than before.

The present invention that solves the above-described problems is a method of cleaning a reactor water supply pipe that cleans the inside of a reactor water supply pipe provided to communicate with the reactor pressure vessel before fuel is loaded into the reactor pressure vessel. And having a piping step of providing a washing water drain pipe so as to branch from the reactor water supply pipe in the middle of the extension of the reactor water supply pipe, and the reactor water supply pipe is connected to the reactor pressure vessel. A first draining step of sending cleaning water into the reactor water supply pipe from the other end side of the reactor water supply pipe opposite to the one end side, and draining the cleaning water through the drain pipe; by feeding washing water from the one end of the reactor water supply pipe to the reactor feedwater pipe, the washing water, and a second drainage step of draining through the drain pipe, the first One of the drainage process and the second drainage process After the draining process is performed, wherein the other one of the drain step.

  ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning method of the reactor water supply pipe which is excellent in washing | cleaning efficiency than before can be provided.

1 is a configuration explanatory diagram of a nuclear power plant to which a method for cleaning a reactor water supply pipe according to an embodiment of the present invention is applied. FIG. It is a flowchart of the process implemented by the cleaning method of the reactor water supply pipe | tube which concerns on embodiment of this invention. It is 1st process explanatory drawing of the cleaning method of the reactor water supply pipe | tube which concerns on embodiment of this invention. It is 2nd process explanatory drawing of the cleaning method of the reactor water supply pipe | tube which concerns on embodiment of this invention. It is 3rd process explanatory drawing of the cleaning method of the reactor water supply pipe | tube which concerns on embodiment of this invention. It is 4th process explanatory drawing of the cleaning method of the reactor water supply pipe | tube which concerns on embodiment of this invention. It is a schematic diagram for demonstrating the washing | cleaning method of the conventional nuclear reactor water supply pipe | tube.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a configuration explanatory diagram of a nuclear power plant to which a method for cleaning a reactor water supply pipe according to this embodiment is applied. In this embodiment, after describing the configuration of a nuclear power plant (nuclear power plant) provided with an improved boiling water reactor (ABWR, Advanced Boiling Water Reactor), in this nuclear power plant (hereinafter simply referred to as “nuclear power plant”). A method for cleaning the reactor water supply pipe will be described.

  FIG. 1 shows an outline of a nuclear power plant under construction to which the cleaning method according to the present embodiment is applied, and shows a state before fuel is loaded. In addition, Fig. 1 shows a steam turbine that constitutes a nuclear power plant, a main steam pipe connecting the reactor pressure vessel and the steam turbine, a generator, an off-gas treatment system, a high-pressure core water injection system, a reactor coolant purification system, and a suppression pool purification. Description of the system, fuel pool, fuel pool cooling and purification system, etc. is omitted.

  As shown in FIG. 1, a nuclear power plant 1 includes an improved boiling water light water reactor 2 (hereinafter simply referred to as a reactor 2), a reactor containment vessel 3 for storing the reactor 2, a condenser 4, It is equipped with.

The nuclear reactor 2 includes a nuclear reactor pressure vessel 2a including a bottomed cylindrical body and an upper mirror. Then, after the reactor water supply pipe 5 cleaning method according to the present embodiment, which will be described in detail later, is performed, in this reactor pressure vessel 2a, from the bottom to the top, a core support plate and an upper lattice (not shown) A plate, a steam separator, a steam dryer, etc. will be arranged. In addition, the code | symbol 2b shown below the reactor pressure vessel 2a of FIG. 1 is the improved control rod drive which drives the control rod (illustration omitted) which has the function of the reactivity control of the fuel with which it loads later, and a reactor scram. A mechanism (FMCRD, Fine Motion Control Rod Drive), and 2c is an internal pump as a recirculation pump with a built-in reactor.
A suppression pool 3 a is provided below the reactor containment vessel 3.

  In the condenser 4, steam generated in the reactor pressure vessel 2 a is sent to a steam turbine (not shown) during the subsequent operation of the reactor 2 (hereinafter sometimes referred to as “reactor operation”). After being generated, the reactor condensate system is configured to cool and condense it when it is sent out from the steam turbine.

  The condenser 4 and the reactor pressure vessel 2 a are connected by a reactor water supply pipe 5. That is, as described in the claims, the reactor water supply pipe 5 is connected to the reactor pressure vessel 2a at one end side thereof and is connected to the condenser 4 at the other end side opposite thereto. Then, the condensate generated by condensing steam during the operation of the reactor is supplied from the condenser 4 into the reactor pressure vessel 2 a through the reactor water supply pipe 5.

  The reactor water supply pipe 5 includes a low-pressure condensate pump 5a, a condensate filter 5b, a condensate demineralizer 5c, and a high-pressure condensate pump 5d on the way from the condenser 4 to the reactor pressure vessel 2a. The low pressure feed water heater 5e, the reactor feed water pump 5f, the high pressure feed water heater 5g, the reactor feed water line first valve 5h, the reactor feed water line second valve 5i, and the reactor feed water line third valve 5j are arranged in this order. Has been placed. Incidentally, the reactor water supply line second valve 5 i and the reactor water supply line third valve 5 j are arranged in the reactor water supply pipe 5 extending in the reactor containment vessel 3.

  In addition, the reactor water supply pipe 5 is provided with a circulation pipe 6 that branches between the high-pressure feed water heater 5g and the reactor water supply line first valve 5h and whose tip is connected to the condenser 4. Yes. The circulation pipe 6 forms a circulation path for returning the condensate sent out from the condenser 4 to the condenser 4 again. The circulation pipe 6 is provided with a supply and condensate recirculation valve 6a. .

  Further, the reactor feed water pipe 5 branches between a condensate demineralizer 5c and a high-pressure condensate pump 5d, and a control rod drive system pipe 7 whose tip is connected to the improved control rod drive mechanism 2b. Is provided. The control rod drive system pipe 7 includes a condensate storage tank 7a, a control rod drive system pump 7b and a water pressure control unit 7c from the branch from the reactor water supply pipe 5 toward the improved control rod drive mechanism 2b. Arranged in order.

  Next, a method for cleaning the reactor water supply pipe 5 in the nuclear power plant 1 will be described with reference to FIGS. FIG. 2 is a flowchart of steps performed in the method for cleaning a reactor water supply pipe according to this embodiment. FIG. 3 is a first process explanatory diagram of the method for cleaning a reactor water pipe according to this embodiment. FIG. 4 is a second process explanatory diagram of the method of cleaning the reactor water pipe according to the present embodiment. FIG. 5 is an explanatory diagram of a third step of the method for cleaning the reactor water supply pipe according to the present embodiment. FIG. 6 is an explanatory diagram of a fourth step of the method of cleaning the reactor water supply pipe according to the present embodiment. In the description of FIGS. 2 to 6, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, the method for cleaning the reactor water supply pipe 5 in the present embodiment includes a step of installing a drain pipe 8 (see FIG. 3) (step S <b> 1) and the condenser 4, as will be described in detail later. The first step having a step of storing the cleaning water W (step S2) and the step of circulating the cleaning water W in the condenser 4 through the reactor water supply pipe 5 and the circulation pipe 6 (step S7). The second step, the step of passing the cleaning water W in the condenser 4 through the reactor water supply pipe 5 and the drain pipe 8 (step S15), and the supplied cleaning water W to the suppression pool 3a A third step having a step of draining (step S16), a step of storing the wash water W in the reactor pressure vessel 2a (step S19), and the wash water W in the reactor pressure vessel 2a Suppression via pipe 5 and drain pipe 8 It is mainly composed of a fourth step comprising the step (step S23) to drain the Lumpur 3a.

Below, the washing | cleaning method of the reactor water supply pipe | tube 5 in this embodiment is divided and demonstrated to a 4th process from a 1st process.
As shown in FIGS. 2 and 3, in the first step of the cleaning method, first, the cleaning water drain pipe 8 is installed so as to branch from the reactor water supply pipe 5 (step S1 in FIG. 2). One end of the drain pipe 8 in the present embodiment is attached to the reactor water supply line second valve 5i. The drainage pipe 8 is removed from the reactor water supply line second valve 5i after the cleaning method according to the present embodiment is performed. At this time, the drainage pipe 8 is restored to the reactor water supply line second valve 5i. If it can be attached to the reactor water supply line second valve 5i as much as possible, the attachment method is not particularly limited. Therefore, the drain pipe 8 can also be attached to the reactor water supply line second valve 5i via a jig. Note that the reactor water supply line second valve 5i with the drainage pipe 8 attached does not function as a valve until the drainage pipe 8 is later removed and restored, and the drainage pipe 8 for the reactor water supply pipe 5 is restored. It functions as a three-way joint. And the other end of the drain pipe 8 branched from the reactor water supply pipe 5 through the reactor water supply line second valve 5i is opened in the suppression pool 3a. Such a drain pipe 8 is provided with a drain line valve 8a.

  A filter (not shown) is attached to the drain pipe 8. As will be described later, the filter filters foreign matter in the reactor water supply pipe 5 contained in the waste water after washing the reactor water supply pipe 5, so that this foreign matter is introduced into the suppression pool 3 a via the drain pipe 8. It is intended not to be brought in. By the way, this filter can be omitted when it is assumed that the suppression pool 3a is cleaned after the cleaning method of the present embodiment is performed.

  In the first step, the cleaning water W (pure water) is stored in the condenser 4 (step S2 in FIG. 2). Incidentally, in this embodiment, the wash water W is introduced into the condenser 4 from the connection portion of the condenser 4 with the steam outlet pipe to which the steam outlet pipe of the steam turbine to be disposed later is connected. Is done.

  Next, as shown in FIGS. 2 and 4, in the second step, circulation is performed prior to cleaning of the reactor water supply pipe 5 accompanied by drainage from the drain pipe 8, which is one of the main features of the present invention described above. The circulation system through the pipe 6, that is, the reactor water supply pipe 5 indicated by a thick line in FIG. 4 and the circulation pipe 6 branched from this are cleaned.

  In the second step, first, the reactor water supply line first valve 5h is closed, and the feed and condensate recirculation valve 6a is opened (step S3 in FIG. 2). Although not shown, a line valve provided in the middle of the extension of the control rod drive system pipe 7 is closed.

  Next, by starting the low-pressure condensate pump 5a (step S4 in FIG. 2), the wash water W in the condenser 4 is supplied to the reactor water supply pipe 5 indicated by the thick line in FIG. (Step S5 in FIG. 2). At this time, the air in the circulation system is vented through a vent line (not shown) provided at appropriate positions of the reactor water supply pipe 5 and the circulation pipe 6 (step S5 in FIG. 2). Then, once the low-pressure condensate pump 5a is stopped and the vent line is closed, the pump 5a is restarted (step S6 in FIG. 2). As a result, the cleaning water W in the condenser 4 is circulated so as to return to the condenser 4 through the reactor water supply pipe 5 and the circulation pipe 6 indicated by the bold lines in FIG. 4 (FIG. 2). Step S7). Then, after the low-pressure condensate pump 5a is driven until the washing water W in the condenser 4 reaches an amount of water that circulates in the circulation system for several cycles, the pump 5a is stopped again (step S8 in FIG. 2). The second step is finished.

  In the cleaning method according to the present embodiment, the reactor feed water pipe 5 and the circulation pipe 6 as well as the low pressure condensate pump 5a, the high pressure condensate pump 5d, the low pressure feed water heater 5e, the reactor are performed by performing the second step. The feed water pump 5f, the high-pressure feed water heater 5g, and the feed / condensate recirculation valve 6a are washed. Incidentally, foreign matters (including water-soluble salts) contained in the washing water W after washing them are collected by the condensate filter 5b and the condensate demineralizer 5c when the washing water W circulates in the circulation system. It is collected.

  Next, as shown in FIGS. 2 and 5, in the third step, “any one of the first drainage step and the second drainage step” in the claims is performed. Is called. That is, in the third step in the present embodiment, the cleaning water W is sent into the reactor water supply pipe 5 from the side connected to the condenser 4 (the other end side), and the cleaning water W is supplied to the drain pipe 8. The 1st drainage process drained through is performed.

  In this third step, the feed water / condensate recirculation valve 6a, the reactor water line third valve 5j and the drain line valve 8a are closed and the reactor water line first valve 5h is opened (step S9 in FIG. 2). ). In addition, the said line valve (illustration omitted) provided in the middle of extension of the control rod drive system piping 7 is maintaining the closed state. Incidentally, the reactor water supply line second valve 5i functions as a three-way joint as described above.

Next, by starting the low-pressure condensate pump 5a (step S10 in FIG. 2), the wash water W in the condenser 4 is filled in the reactor water supply pipe 5 indicated by the bold line in FIG. 5 (FIG. 2). Step S11). Further, the inside of the drain pipe 8 on the upstream side of the drain line valve 8a is also filled with washing water (step S11 in FIG. 2). At this time, the reactor water supply pipe 5 and the drain pipe 8 are vented through a vent vent (not shown) provided in the drain line valve 8a (step S11 in FIG. 2). And in this 3rd process, the low-pressure condensate pump 5a is once stopped (step S12 of FIG. 2). Next, after closing the air vent, the drain line valve 8a is opened (step S13 in FIG. 2), and the pump 5a is restarted (step S14 in FIG. 2).
As a result, the cleaning water W in the condenser 4 flows through the reactor water supply pipe 5 and the drain pipe 8 indicated by the thick lines in FIG. 5 (step S15 in FIG. 2), and then the cleaning water W is Then, the water is drained into the suppression pool 3a (step S16 in FIG. 2).

In the cleaning method according to the present embodiment, by performing the third step, the reactor water supply line No. 2 from the branch portion of the circulation pipe 6 in the reactor water supply pipe 5 is not cleaned in the second step. The reactor water supply pipe 5 up to the valve 5i is cleaned. Of course, the reactor water supply pipe 5 constituting the circulation system cleaned in the second step is also cleaned again.
Incidentally, the foreign matters contained in the washing water W after washing them are collected and removed by the filter (not shown) provided in the drain pipe 8.

Then, after draining a predetermined amount of wash water W from the condenser 4 through the drain pipe 8 into the suppression pool 3a, the low-pressure condensate pump 5a is stopped again and the drain line valve 8a is closed (FIG. 2). Step S17), the third step ends.
The amount of the washing water W used in the third step is assumed to be the same amount as the amount of the washing water W stored in the condenser 4, but the washing water W is added to the condenser 4. The amount of the cleaning water W can be increased by further adding.

  Next, as shown in FIG. 2 and FIG. 6, in the fourth step, “the other draining step of the first draining step and the second draining step” described in the claims is performed. Is called. That is, in the fourth step in the present embodiment, the cleaning water W is sent into the reactor water supply pipe 5 from the side (one end side) connected to the reactor pressure vessel 2a, and this cleaning water W is discharged to the drain pipe 8. A second drainage process is performed for draining through.

  In the fourth step, first, the reactor water supply line third valve 5j is closed (step S18 in FIG. 2). Next, the wash water W is stored so as to reach a predetermined water level in the reactor pressure vessel 2a (step S19 in FIG. 2). Specifically, the predetermined water level is above a connection portion where the reactor water supply pipe 5 is connected to the reactor pressure vessel 2a, and the washing water is washed by the head of the washing water W in the reactor pressure vessel 2a. W is adjusted so as to flow through the reactor water supply pipe 5 at a flow rate at which a predetermined cleaning effect is exhibited.

  Incidentally, the supply path of the cleaning water W when storing the cleaning water W in the reactor pressure vessel 2a is not particularly limited as long as it does not pass through the reactor water supply pipe 5, for example, a state in which the upper mirror is removed. The cleaning water W may be directly injected into the reactor pressure vessel 2a, or the cleaning water W of the condenser 4 may be supplied via the control rod drive system piping 7 and the improved control rod drive mechanism 2b. It may be supplied.

  Next, in the fourth step, the reactor water supply line third valve 5j is opened with the reactor water supply line first valve 5h and the drain line valve 8a closed (step S20 in FIG. 2). As a result, the head of the cleaning water W in the reactor pressure vessel 2a is vented through a vent vent (not shown) provided in the drain line valve 8a, and is upstream of the drain line valve 8a. The inside of the drain pipe 8 and the reactor water supply pipe 5 from the reactor water supply line second valve 5i to the reactor pressure vessel 2a are filled with the cleaning water W (step S21 in FIG. 2).

  Thereafter, by opening the drain line valve 8a (step S22 in FIG. 2), the cleaning water W in the reactor pressure vessel 2a flows through the reactor water supply pipe 5 and the drain pipe 8 indicated by the thick lines in FIG. The water is drained into the suppression pool 3a (step S23 in FIG. 2). At this time, in order to maintain the predetermined water level of the cleaning water W of the reactor pressure vessel 2a, the reactor pressure vessel 2a has cleaning water according to the amount of the cleaning water W drained from the drain pipe 8. It is desirable that W is added. In addition, the addition of the cleaning water W into the reactor pressure vessel 2a is performed by a route other than the reactor water supply pipe 5 described above, for example, the cleaning water directly into the reactor pressure vessel 2a with the upper mirror removed. The cleaning water W of the condenser 4 may be supplied via the control rod drive system piping 7 and the improved control rod drive mechanism 2b.

  In the cleaning method according to the present embodiment, by performing this fourth step, cleaning is not performed in the second step and the third step, from the reactor water supply line second valve 5i to the reactor pressure vessel 2a. The reactor water supply pipe 5 and the reactor water supply line third valve 5j are cleaned.

Then, after the washing water W having a predetermined amount of water is drained from the reactor pressure vessel 2a through the drain pipe 8 into the suppression pool 3a, the fourth step is finished.
Note that the amount of the cleaning water W used in the fourth step is not particularly limited as long as the reactor water supply pipe 5 can be sufficiently cleaned.

According to the method for cleaning the reactor water supply pipe 5 according to the present embodiment as described above, the following operational effects can be achieved.
In the conventional cleaning method (for example, refer to Patent Document 1), the inside of the reactor water supply pipe 15 is cleaned by causing the cleaning water fed from one end side of the reactor water supply pipe 15 (see FIG. 7) to flow out from the other end side. .
On the other hand, in the cleaning method according to the present embodiment, one end side of the reactor water supply pipe 5 and the other are arranged so that the cleaning water W is drained from the drain pipe 8 provided in the middle of the extension of the reactor water supply pipe 5. The cleaning water W is fed into the reactor water supply pipe 5 from two directions with the end side. Therefore, in the cleaning method according to the present embodiment, the pressure loss of the cleaning water W flowing through the reactor water supply pipe 5 can be reduced as compared with the conventional cleaning method (for example, see Patent Document 1). As a result, the flow rate of the cleaning water W can be increased. Therefore, according to the cleaning method of the reactor water supply pipe 5 according to the present embodiment, the cleaning efficiency of the reactor water supply pipe 5 is superior to the conventional cleaning method (see, for example, Patent Document 1).

  In the conventional cleaning method (for example, see Patent Document 1), the temporary pool 13 (see FIG. 7) is arranged in a limited narrow space in the reactor pressure vessel 12a (see FIG. 7). In order to collect a large amount of waste water after washing the furnace water supply pipe 15 (see FIG. 7), its capacity is small. In contrast, in the cleaning method according to the present embodiment, the cleaning water is drained through the drain pipe 8 provided in the middle of the reactor water supply pipe 5 that extends outside the reactor pressure vessel 2a. Therefore, according to the cleaning method according to the present embodiment, unlike the conventional cleaning method (for example, see Patent Document 1), it is possible to secure a drainage destination for collecting a large amount of drainage.

  In addition, according to the cleaning method according to the present embodiment, unlike the conventional cleaning method (see, for example, Patent Document 1), the cleaning water is drained outside the reactor pressure vessel 2a. It is possible to avoid the foreign matter in the tube 5 being brought into the reactor pressure vessel 2a.

  Moreover, according to the cleaning method according to the present embodiment, the cleaning water W after cleaning is collected in the temporary pool 13 (see FIG. 7) provided in the conventional reactor pressure vessel 12a (see FIG. 7). In contrast, since there is no need to worry about the overflow, the reactor water pipe 5 can be washed with a large amount of washing water W flowing at a high flow rate, and the conventional washing method (for example, see Patent Document 1). Also, the cleaning efficiency of the reactor water supply pipe 5 is excellent.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, It can implement with a various form.
In the embodiment, after the inside of the reactor water supply pipe 5 is cleaned by the first draining process in which the cleaning water W is sent from the condenser 4 side to the reactor water supply pipe 5, the cleaning water W is supplied from the reactor pressure vessel 2a side. Although the cleaning method for cleaning the inside of the reactor water supply pipe 5 by the second drainage process sent to the reactor water supply pipe 5 has been described, the present invention supplies the cleaning water W to the reactor water supply pipe 5 from the reactor pressure vessel 2a side. After the inside of the reactor water supply pipe 5 is cleaned by the second draining process to be sent, the inside of the reactor water supply pipe 5 is cleaned by the first draining process of sending the cleaning water W from the condenser 4 side to the reactor water supply pipe 5. It can also be configured.

  Moreover, in the said embodiment, although the drainage pipe 8 was provided so that it might branch from the reactor water supply pipe 5 in the reactor containment vessel 3, this invention branches from the reactor water supply pipe 5 outside the reactor containment vessel 3. Thus, the drain pipe 8 can be provided.

  Further, in the present invention, in the case where the drainage pipe 8 is provided so as to branch from the reactor water supply pipe 5 outside the reactor containment vessel 3, a large-capacity drainage recovery tank is separately provided outside the reactor containment vessel 3. It can be configured.

  Moreover, in the said embodiment, after attaching the drain pipe 8 to the reactor water supply pipe | tube 5 at a 1st process, the reactor water supply pipe | tube 5 of a 2nd process is wash | cleaned, but this invention is an atom of a 2nd process. The structure which attaches the drainage pipe 8 to the reactor water supply pipe 5 after washing | cleaning the reactor water supply pipe 5 may be sufficient.

  In the above embodiment, the low-pressure condensate pump 5 a is activated in order to allow the cleaning water W in the condenser 4 to flow through the reactor water supply pipe 5. The pump is not limited to the low-pressure condensate pump 5a as long as the pump is provided in the middle of the extension. That is, the pump for flowing the cleaning water W in the condenser 4 to the reactor feed pipe 5 is at least one of the low pressure condensate pump 5a, the high pressure condensate pump 5d, and the reactor feed water pump 5f. Good.

1 Nuclear power plant 2 Improved boiling water light water reactor (reactor)
2a Reactor pressure vessel 2b Improved control rod drive mechanism 3 Reactor containment vessel 3a Suppression pool 4 Condenser 5 Reactor feed pipe 5a Low pressure condensate pump 5b Condensate filter 5c Condensate demineralizer 5d High pressure condensate pump 5e Low pressure feed water heater 5f Reactor feed water pump 5g High pressure feed water heater 5h Reactor feed line 1st valve 5i Reactor feed line 2nd valve 5j Reactor feed water 3rd valve 6 Circulation pipe 6a Feed and condensate recirculation valve 7 Control rod drive system piping 7a Condensate storage tank 7b Control rod drive system pump 7c Water pressure control unit 8 Drain pipe 8a Drain line valve W Wash water

Claims (3)

A reactor water supply pipe cleaning method for cleaning a reactor water supply pipe provided to communicate with a reactor pressure vessel before loading fuel into the reactor pressure vessel,
While having a piping step of providing a drain pipe for cleaning water so as to branch from the reactor water supply pipe in the middle of the extension of the reactor water supply pipe,
The cleaning water is fed into the reactor water supply pipe from the other end side of the reactor water supply pipe opposite to the one end side where the reactor water supply pipe is connected to the reactor pressure vessel. A first drainage step of draining through a drainpipe;
By feeding washing water from the one end of the reactor water supply pipe to the reactor feedwater pipe, the washing water, a second water discharge step of draining through the drain pipe,
Have
A method for cleaning a reactor water supply pipe, wherein either one of the first draining step and the second draining step is performed and then the other draining step is performed. . The method for cleaning a reactor water pipe according to claim 1,
The cleaning water fed into the reactor water supply pipe from the other end side of the reactor water supply pipe is cleaning water stored in advance in a condenser connected to the other end side of the reactor water supply pipe. The cleaning water fed from the one end side of the reactor water supply pipe into the reactor water supply pipe is the cleaning water stored in advance in the reactor pressure vessel connected to the one end side of the reactor water supply pipe. There,
Wash water in the condenser flows through the reactor water supply pipe by driving a pump provided in the reactor water supply pipe between the branch of the drain pipe and the condenser, A cleaning method for a reactor water supply pipe, wherein the cleaning water in the reactor pressure vessel flows through the reactor water supply pipe by a head of the cleaning water stored in the reactor pressure vessel. In the cleaning method of the reactor water supply pipe according to claim 1 or 2,
A method of cleaning a reactor water supply pipe, wherein a tip end portion of the drain pipe branched from the reactor water supply pipe is opened in a suppression pool included in a reactor containment vessel.

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